Figuring out your daily calorie needs can be confusing. The number of calories you need each day to maintain your current weight is called your maintenance calories. This article will walk you through how to calculate your maintenance calories and provide tips for determining your calorie needs for weight loss or muscle gain.
What are maintenance calories?
Your maintenance calories are the number of calories you need in a day to maintain your current weight. This is the energy your body burns through your basal metabolic rate (the calories used to run basic bodily functions), daily activities, and exercise.
When you consume the same number of calories that you burn, your weight will remain stable. If you consume more calories than you burn, you will gain weight. And if you consume fewer calories than you burn, you will lose weight.
How do I calculate my maintenance calories?
There are a few methods you can use to estimate your daily calorie needs:
Harris-Benedict equation
The Harris-Benedict equation is one of the most commonly used formulas to calculate your basal metabolic rate (BMR). Your BMR is the minimum number of calories your body needs to perform essential functions like breathing, circulating blood, and regulating body temperature.
The Harris-Benedict equation factors in your age, sex, height, and weight. Here is the equation:
For men:
BMR = 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) – (5.677 x age in years)
For women:
BMR = 447.593 + (9.247 x weight in kg) + (3.098 x height in cm) – (4.330 x age in years)
To get your maintenance calories, multiply your BMR by an activity factor:
- Sedentary (little or no exercise): BMR x 1.2
- Lightly active (light exercise 1-3 days/week): BMR x 1.375
- Moderately active (moderate exercise 3-5 days/week): BMR x 1.55
- Very active (hard exercise 6-7 days/week): BMR x 1.725
- Extremely active (very hard exercise and physical job): BMR x 1.9
Mifflin-St Jeor equation
The Mifflin-St Jeor equation is also commonly used to calculate BMR. It considers the same factors as Harris-Benedict but is more accurate for people who are overweight or obese.
For men:
BMR = 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) + 5
For women:
BMR = 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) – 161
As with the Harris-Benedict equation, multiply your BMR by an activity factor to get your total daily energy expenditure.
Katch-McArdle formula
The Katch-McArdle formula calculates BMR based on your lean body mass. It requires knowing your body fat percentage, which can be estimated using skin fold calipers or tools like bioelectrical impedance analysis scales.
The Katch-McArdle formula is:
BMR = 370 + (21.6 x lean mass in kg)
Lean mass = Total weight x (1 – body fat percentage)
Again, multiply your BMR by an activity factor to estimate your total calorie needs.
Online calculators
There are many calorie calculator tools online that will estimate your maintenance calories based on the formulas above. You simply plug in details like your age, weight, height and activity level.
Some examples include:
Tracking calories
One of the best ways to determine your personal maintenance calories is to track your regular calorie intake and weight over time. This method takes trial and error, but can provide a very accurate estimate.
To use this method:
- Track your calories consumed each day for 1-2 weeks without changing your normal eating habits.
- Track your weight at the end of each week.
- Adjust your calorie intake up or down by 100-200 calories if your weight goes up or down.
- Continue adjusting weekly until your weight stabilizes.
The number of calories you’re eating once your weight stabilizes is a close approximation of your maintenance calories.
Factors that influence maintenance calories
Your calorie needs can vary significantly based on many factors:
Body size and composition
People who have a higher amount of muscle mass or are taller in stature generally require more calories. Fat tissue requires less energy to maintain than muscle.
Age
As you age, your metabolism naturally slows and your calorie needs decrease. For example, a 40 year old woman needs fewer calories than a 25 year old woman of the same height and weight.
Sex
Due to differences in body composition, men generally need more calories than women. For example, a man at 5’10” tall requires approximately 400 more daily calories than a woman of the same height.
Activity level
The more active you are, the more calories your body needs. Exercise, sports, an active job like construction work or farming, and even fidgeting can all increase your calorie expenditure and needs.
Climate and temperature
Colder environments and seasons require more energy to regulate body temperature. So you burn more calories in the winter than summer.
Additionally, more calories are needed to cool the body in hotter climates. Air conditioning lowers calorie needs in summer.
Pregnancy and breastfeeding
During pregnancy, calorie needs increase to support fetal growth and development. An additional 300 calories per day are recommended in the 2nd trimester and 450 calories in the 3rd trimester.
Breastfeeding women also require an extra 500 calories per day to make milk.
Medical conditions
Some conditions like hyperthyroidism and diabetes can speed metabolism and increase calorie needs. Others like hypothyroidism can slow metabolism and decrease needs.
Tips for determining your calorie needs
Here are some tips when trying to narrow in on your personal maintenance calories:
- Use one of the formulas above to get a starting estimate.
- Track your calories and weight over time to refine your number.
- Focus on your trends over several weeks, not day-to-day changes.
- Adjust your calories gradually by 100-200 calories at a time.
- Be consistent with your activity level from week to week.
- Consider getting metabolic testing or consulting a doctor or dietitian if needed.
Changing calorie intake for weight goals
Once you know your maintenance calories, you can adjust your intake to align with your weight goals:
Weight loss
To lose weight, you need a calorie deficit or to consume fewer calories than you burn:
- Mild deficit of 10-20% or 200-500 calories below maintenance for slow weight loss of 1-2 pounds per week.
- Moderate deficit of 20-30% or 500-1,000 calories below maintenance for more aggressive loss of 2-3 pounds per week.
- Large deficits over 30% are difficult to sustain over long periods.
Weight gain
To gain weight, you need a calorie surplus or more calories than your body needs:
- Surplus of 10-20% or 200-500 calories above maintenance for slow weight gain.
- Larger surpluses promote faster weight gain but with more fat.
- Aim for controlled weight gain of 1-2 pounds per week.
Maintaining muscle
When in a calorie deficit, protein intake can help minimize muscle loss. Get at least 0.5-1 grams of protein per pound of body weight per day.
Sample calorie needs
To illustrate the impact of different factors, here are some sample maintenance calories for different profiles:
| Profile | Maintenance Calories |
|---|---|
| 25 year old male, 5’10”, 160 lbs, lightly active | 2,400 calories |
| 45 year old female, 5’4″, 125 lbs, moderately active | 1,950 calories |
| 35 year old male, 6’0″, 200 lbs, very active | 3,000 calories |
Tracking progress over time
Regularly reevaluate your calorie needs, especially if your activity, body composition or goals change over time. Weight loss can slow your metabolism, so you may need to adjust calories further along your journey.
Weigh yourself weekly and measure body composition monthly or quarterly if possible. Adjust your calories based on your progress and trends over several weeks.
Incorporating diet breaks
During long term calorie restriction, taking periodic diet breaks at maintenance calories can boost leptin levels, reverse metabolic slowdown, and ultimately help sustain weight loss.
Aim for a diet break of 1-2 weeks at maintenance calories every 3-6 months if following a reduced calorie diet for weight loss.
Using an online calorie calculator
Online calorie calculators can provide a starting estimate, but your individual needs may vary. Use a calculator estimate as a baseline, then adjust from there based on your own data.
Enter your details as accurately as possible into the calculator. Be honest about your activity level – most people overestimate. Choose the “maintain weight” option for maintenance calories.
Re-check your calorie needs every month or two. Needs can change over time as you age, gain/lose weight, or increase/decrease activity.
Calorie cycling for sustained weight loss
Calorie cycling involves varying your calorie intake over the course of a week to promote weight loss. It aims to prevent metabolic slowdown that can occur with sustained calorie restriction.
A sample calorie cycling plan for weight loss:
| Day | Calorie Intake |
|---|---|
| Monday | 500 below maintenance |
| Tuesday | 750 below maintenance |
| Wednesday | 500 below maintenance |
| Thursday | 750 below maintenance |
| Friday | 500 below maintenance |
| Saturday | Maintenance |
| Sunday | Maintenance |
Common calorie myths
There are many myths and misconceptions about calories. Here are some facts:
- Myth: All calories are created equal. Fact: Calories from protein, carbs, fat, and alcohol affect the body differently.
- Myth: Lower calorie intake always causes weight loss. Fact: Severely restricting calories can slow your metabolic rate.
- Myth: You need three meals a day. Fact: Meal timing and frequency have minimal effect on weight.
- Myth: Slow, steady weight loss is worse. Fact: Quick weight loss often causes loss of water and muscle rather than fat.
Should I track macros along with calories?
Tracking macros (protein, carbs, fat) can help optimize body composition and health, beyond just calories:
- Higher protein for building/retaining muscle.
- Moderate carbs to support exercise performance.
- Healthy fats for hormones, absorption of fat-soluble vitamins.
Aim for a balanced intake of each that aligns with your fitness goals and activity level. Macro tracking takes more effort but offers a level of precision calories alone do not.
Key takeaways
- Maintenance calories keep your weight stable by matching energy intake and expenditure.
- Equations like Harris-Benedict provide a starting point but tracking intake over time gives the most accurate number.
- Body size, age, sex, activity level and other factors all influence calorie needs.
- Adjust your calories up or down to align with your goals of weight loss, gain or maintenance.
- Re-evaluate your needs frequently over time as your stats change.
